Mounting of dozer blades

ABSTRACT

This specification discloses a method and a mounting assembly for attaching a dozer blade to a tractor characterized by enabling the blade to be set to a desired degree of pitch and tilt without inducing twist into or causing other undesirable concentrations of stresses in the mounting assembly and by enabling side booms of the mounting assembly to be fit closely to the tractor on which the blade is mounted. The mounting assembly has a rigid frame for attaching to the tractor; an independent pitching means connecting the top center of the blade with the rigid frame for effecting pitch of the blade; and independent tilting means including at at least one end of the blade a bell crank connected therewith for moving that end of the blade up and down with respect to the rigid frame in response to torque from a means inter-connected between the other end of the bell crank and the rigid frame and operable to rotate the bell crank about a fulcrum axis on the rigid frame. Also disclosed is a preferred embodiment in which each end of the blade is individually movable up or down by rotation of its respective bell crank about respective fulcrum axes on the rigid frame. Other elements necessary or advisable for efficient operation are also disclosed, even though some are conventional.

United States Patent [151 3,662,841 Molby et al. May 16, 1972 4] MOUNTING 0F DOZER BLADES Primary Examinen-Robert E. Pulfrey 72 Inventors: Lloyd A. Molby; Lloyd L. Magown; Larry T. Steiner, all of Longview, Tex.

[73] Assignees R. G. Le Torneau, lnc., Longview, Tex. [22] Filed: Feb; 2, 1970 [21] Appl. No.: 7,830

[52] US. Cl ..172/804, 172/806 [51] Int. Cl. t ..E02i 3/76 [58] Field of Search l 72/801-809; 37/1 17.5; 214/778 [56] References Cited UNITED STATES PATENTS 3,222,804 12/1965 Kuhl 1 72/803 3,213,553 10/1965 Foy ..172/804 2,775,831 1/1957 Rockwell..... 172/803 3,487,884 1/1970 Volberding. 172/803 3,199,236 8/1965 Bartel et al ..37/117.5 X 3,181,430 5/1965 Freedy et al. 214/778 UX 2,734,292 2/1956 Graves ..37/l44 3,296,721 l/l967 Coontz. 172/801 2,160,596 5/1939 Bleu ..172/804 3,552,313 l/1971 v.leschke ..10l/218 Attorney-Wofford and Felsman [57] ABSTRACT This specification discloses a method and a mounting assembly for attaching a dozer blade to a tractor characterized by enabling the blade to be set to a desired degree of pitch and tilt without inducing twist into or causing other undesirable concentrations of stresses in the mounting assembly and by enabling side booms of the mounting assembly to be fit closely to the tractor on which the blade is mounted, The mounting assembly has a rigid frame for attaching to the tractor; an independent pitching means connecting the top center of the blade with the rigid frame for effecting pitch of the blade; and independent tilting means including at at least one end of the blade a bell crank connected therewith for moving that end of the blade up and down with respect to the rigid frame in response to torque from a means inter-connected between the other end of the bell crank and the rigid frame and operable to rotate the bell crank about a fulcrum axis on the rigid frame. Also disclosed is a preferred embodiment in which each end of the blade is individually movable up or down by rotation of its respective bell crank about respective fulcrum axes on the rigid frame. Other elements necessary or advisable for efficient operation are also disclosed, even though some are conventionai.

5 Claims, 4 Drawing Figures PATENTEBMY 16 van SHEET 2 BF 2 r w 3% a M WW M MOUNTING OF DOZER BLADES BACKGROUND. OF THE INVENTION l. Field of the Invention This invention relates to assemblies for bulldozers, or large tractors; and, particularly,'to assemblies for mounting a dozer blade thereon.

2. Description of the Prior Art Mounting a dozer blade on a tractor for bulldozing a 1 straight, level swath presents no problem. To mount a tiltable blade capable of sustaining the forces of thrust involved in bulldozing has created problems. The problems are further complicated if it is desired to also provide for independently pitching the blade about itslongitudinal axis.

It is known in the prior art to provide side diagonal braces that may or may not be lengthened or shortened between the push arms, or side booms, mounted to the side of the tractor and the blade. The side booms may be connectedytogether by structure such as crosspieceand brace to provide a mounting assembly that will prevent lateral shifting of the blade during the scraping of a swath. Ordinarily, the side diagonal braces are of variable length to impart tilt to the blade. Such tilting imparts a twist to the mounting assembly and builds up stresses in the side booms. The concentration of stresses caused by the twist and the compression attending the bulldozing can effect severe damage, and even breakage of the side booms or associated structure. Also, the twisting required somewhat larger clearance between the side booms and the tractor than desired.

To try to alleviate this buildup of stresses, independently mounted cradles have been employed. The sides of such a cradle may be independently raised and lowered to effect a desired degree of tilt in the dozer blade. The cradle is attached to the tractor at a single universal mounting point. Difficulty has been encountered with the concentration of stresses at the single universal mounting point of the cradle. Moreover, since the cradle tilts and is subject to lateral shifting there must be a relatively large clearance between the sides of the cradle and the tractor.

Thus, the prior art assemblies for mounting dozer blades on a tractor have not been altogether satisfactory in providing independently controllable pitch and tilt of the dozer blade without inducing twist or undesirable stress concentrations somewhere in the mounting assembly. Furthermore, the prior art mounting assemblies have not allowed attachment of the side booms to the tractor without larger clearance than desired.

BRIEF DESCRIPTION or THE DRAWINGS FIG. 1 is an isometric view of one embodiment of the invention.

FIG. 2 is an isometric view of an alternate and preferred embodiment of the invention.

FIG. 3 is a side view of a bell crank employed in a preferred embodiment of the invention.

FIG. 4 is a section view showing a self-aligning bearing mounted at one end portion of a dozer blade in accordance with one aspect of the invention.

DESCRlPTlON OF PREFERRED EMBODIMENT(S) It is a particular feature of this invention to provide a method and mounting assembly for mounting a dozer blade onto a tractor that alleviates the difficulties encountered heretofore through twist or a concentration of stress in the mounting assembly by eliminating the twist on the blade, on the side booms, or on the mounting assembly as a whole; yet, provides for independently tilting and pitching the blade to obtain the desired angles of pitch and tilt and allows side booms to fit closely to the sides of the tractor.

In FIG. 1 of the drawings, mounting assembly 11 comprises the major sub-assemblies of a strong rigid frame 13, elevating means 15, dozer blade 17, link means shown as power pitching means 19 and tilting means 21.

Rigid frame 13 is adapted to withstand the force a tractor to which dozer blade 17 is mounted can exert on the dozer blade. Rigid frame 13 consists essentially of side booms 23 and 25, and a strong crosspiece 27 integrally connected with side booms 23 and 25. Corner braces 29 are provided to increase further the strength of rigid frame 13 and prevent sidewise movement and distortion thereof when scraping a swath. Because it has great strength and because it undergoes no twist in tilting blade 17, rigid frame 13 can fit closely to the sides of the tractor. Attachment means 31 are provided for attaching side booms 23 and 25 to a tractor (not shown).

Elevating means 15 comprises hydraulic cylinder 33, piston therewithin, and shaft 35 serving as a lineal extensible member connected with the piston and with midpoint bracket 36 of rigid member 13. Suitable motive power for raising, or elevating, and lowering the outer end portion of rigid frame 13 carrying blade 17 is afforded by high pressure hydraulic fluid suitably routed through lines 37 and 39. By suitably routed" is meant conventional delivery of high pressure fluid through one of the lines to a high pressure side of the piston for movement while the other line is employedto drain fluid from the low pressure side of the piston back to the hydraulic fluid reservoir. The other end of elevating means 15 is connected with the frame of the tractor as a base from which to raise and lower rigid frame 13.

The terminology dozer blade" is employed herein in its general sense to mean a blade assembly having the requisite structural strength to withstand the force generated by the bulldozing, and is in contradistinction to the mere cutting edge portions such as employed on light weight graders. Dozer blade 17 has three mounting means shown as brackets 41, 43, and 45 at, respectively, its top center and at each of its ends adjacent its bottom edge 46. Ordinarily, dozer blade 17 will also have a replaceable cutting edge portion 48 on the leading side of its bottom edge.

Power pitching means 19 connects top center mounting bracket 41 of blade 17 with midpoint bracket 47 of rigid frame 13. Midpoint bracket 47 may be the same as midpoint bracket 36 at which elevating means 15 is connected with rigid frame 13, if desired. Power pitching means 19 comprises hydraulic cylinder 49, piston therewithin and shaft 51 serving as a lineal extensible member. Cylinder 49 is connected with midpoint bracket 47 by a self-aligning bearing 53, the spherical portion effecting the self-alignment being shown in dashed lines. Similarly, shaft 51 is connected with mounting bracket 41 by self-aligning bearing 55. Thus, the pitch of blade 17 about its longitudinal axis is independently controllable by extending or retracting shaft 51 via its piston within hydraulic cylinder 49. Motive power to effect the extension or retraction is supplied by high pressure hydraulic fluid suitably routed through lines 57 and 59. For simplicity and clarity in illustrating other, more significant details, the hydraulic lines are not extended since they are well known.

Tilting means 21 includes at at least one end of blade 17 a bell crank 61 mounted at a fulcrum axis, or fulcrum point 63 on rigid frame 13 for pivotal movement about a transverse axis that extends along crosspiece 27. Lower end 65 of bell crank 61 is connected with mounting bracket 43 of blade 17 by a self-aligning bearing 67. Upper end 69 of bell crank 61 is connected with side boom 23 of rigid frame 13 by way of power means 71. Power means 71 consists of hydraulic cylinder 73, piston therein, and shaft 75 attached to the piston and serving as a lineal extensible member. Shaft 75 is connected to upper end 69 by pin 77. Similarly, the other end of hydraulic cylinder 73 is connected by pin 81 to a mounting bracket 79 attached to side boom 23. Motive power for extending and retracting shaft 75 is supplied by high pressure hydraulic fluid suitably routed through lines 83 and 85. Again, these lines are not extended since they are so well known. Thus, extension of shaft 75 rotates bell crank 61 about fulcrum axis 63 lowering one end of blade 17 and effecting the desired degree of tilt. Conversely, retraction of shaft 75 rotates bell crank 61 in the opposite direction and elevates the one end of blade 17 at which mounting bracket 43 is located. Accordingly, a positive or negative angle of tilt with respect to the horizontal, can be effected about the other end of the blade which is pivotally mounted at a fixed point.

Bracket 45 at the other end of blade 17 is connected with rigid extension 87 of rigid frame 13, particularly side boom 25, by self-aligning bearing 89.

Thus, blade 17 is mounted at all three of its brackets and the link means is mounted to the rigid frame by self-aligning bearings such that the blade pitch and tilt can be independently controlled without inducing any stress due to twist on the blade or other part of the mounting assembly.

In FIG. 2 there is illustrated a particularly preferred embodiment of the mounting assembly wherein tilting means 21 consists essentially of an assembly at each end of the blade, each assembly including, as previously described, bell crank 61 mounted at a fulcrum axis 63 on rigid frame 13 for pivotal movement about a transverse axis, having lower ends of the respective bell branks connected with respective mounting brackets 43 and 45 at the ends of blade 17; and having respective upper ends connected with respective power means 71. The respective power means are constructed and operated as described hereinbefore to operate the respective bell cranks about their respective fulcrum axes. In this particularly preferred embodiment, one bell crank can be employed to raise one end of blade 17 while the other is employed to lower the other end of blade 17. Accordingly, twice the degree of tilt can be effected with the same length arms in the bell cranks.

When the dozer blade is tilted it is necessary to provide some means to accommodate resulting variations in the distance between the pivot points at the blade end portion mounting means. In accordance with a feature of the invention, this may be accomplished by the arrangement illustrated by FIG. 4. In FIG. 4 there is shown a self-aligning bearing mount which permits limited side play. This bearing mount may be used with the mounting means at one of the blade end portion mounts. The ball portion 44 of the self-aligning bearing 67 is made slidable longitudinally of the shaft 68 between stop blocks 70. Thus, sufficient side play is provided to accommodate variations in the distance between the pivot points at the blade end portion mounting means when the blade is tilted.

In the embodiment illustrated in FIG. 2, other features and construction are as described hereinbefore with respect to FIG. 1, although the hydraulic lines are completely omitted from FIG. 2. Again, all three mounting points of blade 17 as well as the mounting point of the link means to the rigid frame have self-aligning bearings such that no twist or stress is induced in effecting the desired angle of tilt.

In operation of the embodiments illustrated in FIGS. 1 and 2, hydraulic power is supplied to elevating means to properly position shaft 35 to effect the desired height of blade 17. The proper height is effected in a gross way and may be adjusted to exactly the right height, once the desired degree of pitch and tilt of the blade are effected. Power pitching means 19 is operated by sending hydraulic fluid through the respective line to extend shaft 51 to obtain the desired degree of pitch of blade 17 about its longitudinal axis. Similarly, tilting means are operated by sending hydraulic fluid to respective power means 71 to effect the desired degree of tilt of blade 17. As indicated hereinbefore, approximately twice the degree of tilt can be effected by the embodiment of FIG. 2, employing the same length bell cranks, since one power means can be employed to lower one end of the blade while the second power means is being employed to raise the other end of blade 17. Thereafter, the tractor, not shown, is moved forward to scrape the desired swath with the desired angle of tilt. With each repetitive swath, it may be desirable to change the elevation of the blade by activating elevating means 15, or to compensate for small changes effected by altering the degree of tilt or the degree of pitch. Similarly, the degree of pitch may be altered by extending or retracting shaft 51 to obtain the desired amount of scraping and rolling of surface or near surface materials by blade 17. Through independent control of the height, of the degree of pitch, and of the tilt of blade 17, the skill of the operator can be employed to its utmost to effect a high degree of precision in the bulldozing of a swath.

In mounting dozer blade 17 to a tractor, it has been found that great strength is obtainable by forming rigid frame 13 by the following steps. First a piece of bar stock is selected to provide the desired structural strength. At least one end of the bar stock crosspiece typified by crosspiece 27 is then turned down to form a cylindrical portion, which may, if desired, have a reduced diameter as illustrated by exposed cross section of fulcrum point 63. A side boom; such as, side boom 23; having a first flattened end piece 91, FIG. 2, containing an aperture is fitted over the cylindrical portion and the first flattened end piece 91 is attached to the crosspiece 27. If desired, end piece 91 can be fitted over the cylindrical portion and then welded to side boom 23. A second flattened end piece 93 is then emplaced over the cylindrical portion but spaced from the first flattened end piece to define a fulcrum axis therebetween and form a bifurcated end of side boom 23. Second flattened end piece 93 is attached to side boom 23.

In order to emplace bell crank 61 about fulcrum axis 63 so formed, it is imperative that at least a two-piece bell crank be employed. Such a multi-piece bell crank is illustrated in FIG. 3. Therein bell crank 61 has its upper end 69 connected with lower end 65 by bolts 95. Bolts 95 are ordinarily screwed into tapped apertures. Any other means of fastening the at least two pieces of bell crank 61 together may be employed as long as they will sustain the stress to which bell crank 61 is subjected. Ordinarily, a plurality of bolts 95 are required on either side of fulcrum axis 63. If desired, bolts and nuts can be employed although placement of the nuts is made difficult by the close quarters in which the work must be performed.

When only one bell crank is employed at one end of the blade, second side boom; such as, side boom 25 in FIG. 1; is connected to the other end of crosspiece 27. On the other hand, when a second bell crank is employed as illustrated in FIG. 2 the same steps are advantageously used in defining second fulcrum axis 63 at the other end of crosspiece 27, and attaching second bell crank 61. Attachment means 31 may be any of the conventionally employed means for attaching side booms 23 and 25 onto the tractor.

The attaching of the various members; for example, of crosspiece 27 to side booms 23 and 25, of corner braces 29, and of flattened end pieces 91 and 93; are ordinarily effected by welding for greater convenience, strength and rigidity. Other connections; such as, riveting or bolting; can be employed, however, if they will effect the desired structural strength.

The elevating means and the respective power means have been illustrated as hydraulic transducers; such as, piston and cylinder arrangements. Any other transducers which will effect extension of the lineal extensible member can be employed. For example, the elevating means and the power means may comprise an electric motor extending a lineal extensible member; as by rotating a nut engaging threads thereon, or by rotating a gear engaging a lineal gear on the extensible member. It should be mentioned that in some applications it may be desirable to utilize manually operated power means for accomplishing the tilt and pitch adjustments of the dozer blade. Also, in some applications the pitch of the dozer blade may be fixed, in which case the power pitching means 19 may be replaced by a rigid link member connected at its ends via self-aligning bearings to the blade and frame.

The usual materials of construction are employed in fabricating the mounting assembly and the blade described hereinbefore. Ordinarily, steels are preferred because of their structural strength and ready amenability to the various operations; such as, welding, milling and casting.

Although the invention has been described with a certain degree of particularity, it is understood that the present disclosure has been made only by way of example and that numerous changes in the details of construction and the combination and arrangement of parts may be resorted to without departing from the spirit and the scope of the invention.

What is claimed is:

l. A mounting assembly for attaching a'dozer blade to a tractor comprising: I

a. a strong rigid frame adapted to withstand force said tractor can exert on said dozer blade and consisting essentially of side booms terminating with an attachment means for facilitating attachment to said tractor, and a strong crosspiece integrally connected with said side booms;

b. elevating means connected with said rigid frame and adapted for connection with said tractor for raising and lowering an outer end portion of said rigid frame carrying said dozer blade;

c. a dozer blade having three mounting means including one at its top center and one at each of its end portions ad jacent its bottom edge;

d. link means including a powered lineal extensible member connecting said top center mounting means of said blade with said rigid frame;

e. tilting means including at at least one end of said blade a bell crank mounted at a fulcrum axis on said rigid frame for pivotal movement about a transverse axis; having one end connected with a mounting means at said one end portion of said blade; and having the other end connected with power means having a lineal extensible member, said power means also being connected with said rigid frame and operable to rotate said bell crank about said fulcrum axis;

f. self-aligning bearings connecting said link means and tilting means to said mounting means and said link means to said rigid frame; and

g. means connecting the other end portion of said blade with said rigid frame, including a self-aligning bearing at the blade mount portion of said means.

2. The mounting assembly of claim 1 wherein said crosspiece of said rigid frame has a terminal cylindrical portion onto which bifurcated ends of said side boom are fitted and rigidly connected, forming said fulcrum axis therebetween and said bell crank comprises two pieces joined together about said fulcrum axis.

3. The mounting assembly of claim 2 wherein said means connecting the other end portion of said blade with said rigid frame is a tilting means including a bell crank mounted at a fulcrum axis on said rigid frame for pivotal movement about a transverse axis and having one end connected with the respective mounting means on said blade and having the other end connected with power means having a lineal extensible member, said power means also being connected with said rigid frame and operable to rotate said bell crank about said fulcrum axis.

4. In a method of mounting a dozer blade, the improvement comprising:

a. forming a rigid frame by:

i. turning down at least one end of a bar stock crosspiece to form a cylindrical portion;

ii. emplacing a first flattened end piece containing an aperture over said cylindrical portion and attaching said flattened end piece to said crosspiece;

iii. attaching a side boom to said first flattened end piece;

iv. emplacing a second flattened end piece over said cylindrical portion but spaced from said first flattened end piece to define a fulcrum axis therebetween and form a bifurcated end for said side boom, and attaching said second flattened end piece to said side boom;

v. attaching a second side boom at the other end of said crosspiece; and

vi. forming attachment means on the respective other ends of said side booms;

. connecting a multi-piece bell crank about said fulcrum XIS;

c. inter-connecting a power means having a lineal extensible member between said side boom having said bifurcated end and the upper end of said bell crank;

d. connecting link means employing a self-aligning bearing with the mid-point of said crosspiece;

e. connecting a dozer blade mounting means employing self-aligning bearings with the lower end of said bell crank, with the other end of said link means and with the other end of said crosspiece;

connecting one end of an elevating means with said rigid frame; and

g. connecting appropriately said elevating means and said attachment means with said tractor.

5. The method of claim 4 wherein said rigid frame is formed by turning down both ends of said crosspiece and attaching at each end a side boom having bifurcated ends as described in step (a) (i)-(iv); and forming at said each end an assembly by joining a multi-piece bell crank about each respective fulcrum axis thus formed; inter-connecting, respectively, power means between said side boom and the upper end of said bell crank; and connecting said dozer blade with the lower end of said bell crank, in accord with steps (b) through (c). 

1. A mounting assembly for attaching a dozer blade to a tractor comprising: a. a strong rigid frame adapted to withstand force said tractor can exert on said dozer blade and consisting essentially of side booms terminating with an attachment means for facilitating attachment to said tractor, and a strong crosspiece integrally connected with said side booms; b. elevating means connected with said rigid frame and adapted for connection with said tractor for raising and lowering an outer end portion of said rigid frame carrying said dozer blade; c. a dozer blade having three mounting means including one at its top center and one at each of its end portions adjacent its bottom edge; d. link means including a powered lineal extensible member connecting said top center mounting means of said blade with said rigid frame; e. tilting means including at at least one end of said blade a bell crank mounted at a fulcrum axis on said rigid frame for pivotal movement about a transverse axis; having one end coNnected with a mounting means at said one end portion of said blade; and having the other end connected with power means having a lineal extensible member, said power means also being connected with said rigid frame and operable to rotate said bell crank about said fulcrum axis; f. self-aligning bearings connecting said link means and tilting means to said mounting means and said link means to said rigid frame; and g. means connecting the other end portion of said blade with said rigid frame, including a self-aligning bearing at the blade mount portion of said means.
 2. The mounting assembly of claim 1 wherein said crosspiece of said rigid frame has a terminal cylindrical portion onto which bifurcated ends of said side boom are fitted and rigidly connected, forming said fulcrum axis therebetween and said bell crank comprises two pieces joined together about said fulcrum axis.
 3. The mounting assembly of claim 2 wherein said means connecting the other end portion of said blade with said rigid frame is a tilting means including a bell crank mounted at a fulcrum axis on said rigid frame for pivotal movement about a transverse axis and having one end connected with the respective mounting means on said blade and having the other end connected with power means having a lineal extensible member, said power means also being connected with said rigid frame and operable to rotate said bell crank about said fulcrum axis.
 4. In a method of mounting a dozer blade, the improvement comprising: a. forming a rigid frame by: i. turning down at least one end of a bar stock crosspiece to form a cylindrical portion; ii. emplacing a first flattened end piece containing an aperture over said cylindrical portion and attaching said flattened end piece to said crosspiece; iii. attaching a side boom to said first flattened end piece; iv. emplacing a second flattened end piece over said cylindrical portion but spaced from said first flattened end piece to define a fulcrum axis therebetween and form a bifurcated end for said side boom, and attaching said second flattened end piece to said side boom; v. attaching a second side boom at the other end of said crosspiece; and vi. forming attachment means on the respective other ends of said side booms; b. connecting a multi-piece bell crank about said fulcrum axis; c. inter-connecting a power means having a lineal extensible member between said side boom having said bifurcated end and the upper end of said bell crank; d. connecting link means employing a self-aligning bearing with the mid-point of said crosspiece; e. connecting a dozer blade mounting means employing self-aligning bearings with the lower end of said bell crank, with the other end of said link means and with the other end of said crosspiece; f. connecting one end of an elevating means with said rigid frame; and g. connecting appropriately said elevating means and said attachment means with said tractor.
 5. The method of claim 4 wherein said rigid frame is formed by turning down both ends of said crosspiece and attaching at each end a side boom having bifurcated ends as described in step (a) (i)-(iv); and forming at said each end an assembly by joining a multi-piece bell crank about each respective fulcrum axis thus formed; inter-connecting, respectively, power means between said side boom and the upper end of said bell crank; and connecting said dozer blade with the lower end of said bell crank, in accord with steps (b) through (e). 